Home About us Contact
|
Home About us Contact | ||
|
|
||
Phosphate Materials (phosphate + material)
Selected AbstractsChemInform Abstract: New Noncentrosymmetric Tellurite Phosphate Material: Synthesis, Characterization, and Calculations of Te2O(PO4)2.CHEMINFORM, Issue 39 2010Min Kyung Kim Abstract The title compound is prepared by solid state reaction of TeO2 and P4O10 (evacuated silica tube, 550 °C, 24 h). [source] Subcutaneous-induced membranes have no osteoinductive effect on macroporous HA-TCP in vivoJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2009Sylvain Catros Abstract Induced Membranes Technique was first described to enhance bone reconstruction of large osseous defects. Previous in vitro studies established their osteoinductive potential, due to the presence of opteoblasts precursors and to high amounts of growth factors contained within. The purpose of this study was to test in vivo the osteoinductive properties of induced membranes on a macroporous HA-TCP in a nonosseous subcutaneous site. Subcutaneous-induced membranes were obtained in 21 rabbits; 1 month later, the membranes were filled with a biphasic calcium phosphate material composed of 75% hydroxyapatite (HA) and 25% ,-tricalcium phosphate associated or not with autograft. Histological and immunohistochemical studies were performed on membrane biopsies. Undecalcified and decalcified sections were qualitatively and quantitatively analyzed. 45Ca uptake was observed and quantified on the sections using microimager analysis. Dense vascularity was found in the induced membranes. New bone formation was detected in the HA-TCP,+,autograft samples and increased significantly from 3 to 6 months (p,<,0.05). No bone was detected in the biomaterial graft alone in the induced membranes at any time. This study showed that induced membranes placed in a nonosseous site have no osteoinductive properties on a macroporous biphasic calcium phosphate biomaterial. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:155,161, 2009 [source] Structural Diversity in Organotin Compounds Derived from Bulky Monoaryl Phosphates: Dimeric, Tetrameric, and Polymeric Tin Phosphate ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 9 2008Ramaswamy Murugavel Abstract Monoaryl phosphates with a bulky aryl substituent have been used to synthesize new organotin clusters and polymers. The equimolar reaction between 2,6-diisopropylphenylphosphate (dipp-H2) and Me2SnCl2 in ethanol at 25 °C leads to the formation of [Me2Sn(,3 -dipp)]n (1), while the reaction of 2,6-dimethylphenylphosphate (dmpp-H2) with Me2SnCl2 in either a 1:1 or 2:1 molar ratio proceeds to produce exclusively [Me2Sn(,-dmpp-H)2]n·nH2O (2). Compounds 1 and 2 are 1D polymers with different architectures. In compound 1, the tin atom is five-coordinate (trigonal bipyramidal). Each dipp ligand bridges three different tin atoms to form an infinite ladder-chain structure. In 2, each six-coordinate (octahedral) tin atom is surrounded by four phosphate oxygen atoms originating from four different bridging dmpp-H ligands, thus forming a spirocyclic coordination polymeric chain. The use of nBu2SnO as the diorganotin source in its reaction with dipp-H2 leads to the isolation of dimeric [nBu2Sn(,-dipp-H)(dipp-H)]2 (4), which contains a central Sn2O4P2 unit. There are two chemically different half molecules of 4 in the asymmetric part of the unit cell and hence it actually exists as a 1:1 mixture of [nBu2Sn(,-dipp-H)(dipp-H)]2 and [nBu2Sn(,-dipp)(dipp-H2)]2 in the solid state. The reaction of the monoorgano tin precursor nBuSn(O)(OH)·xH2O with dipp-H2 takes place in acetone at room temperature to yield the tetrameric cluster 5, which has different structures in the solution and in the solid state. 31P NMR spectroscopy clearly suggests that 5 has the formula [nBu4Sn4(,-O)2(,-dipp-H)8] in solution. The single-crystal X-ray diffraction studies in the solid state, however, reveal that compound 5 exists as [nBu4Sn4(,-OH)2(,-dipp-H)6(,-dipp)2]. The use of compounds 1,4 as possible precursors for the preparation of ceramic tin phosphate materials has been investigated. The thermolysis of 1 at 500 °C leads to the formation of quantitative amounts of Sn2P2O7, while the thermolysis of 2, 3, and 4 under similar conditions results in the formation of SnP2O7. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Amine-Intercalated Layered SnII Phosphates with Open-Framework StructuresEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2006Padmini Ramaswamy Abstract Three new SnII phosphate materials, [NH3(CH2)3NH2(CH2)2NH2(CH2)3NH3]·2[Sn2P2O8] (I), [(N2C5H14)2][Sn4P4O16]·3H2O (II) and [(N2C5H14)][Sn2P2O8]·H2O (III), have been synthesised by means of hydrothermal methods using N,N, -bis(3-aminopropyl)ethylenediamine (BAPEN; for I) and homopiperazine (H-PIP; for II and III), respectively, as the structure-directing organic amines. The solids I,III have layered architectures. The structures of all three compounds consist of strictly alternating vertex-sharing trigonal-pyramidal SnO3 and tetrahedral PO4 moieties forming infinite layers possessing apertures bound by 4- and 8-T atoms (T = Sn, P). The distorted 4- and 8-membered apertures within the layers suggest the subtle influence of the lone-pair of electrons of SnII on the structure. The interlamellar space is occupied by the protonated organic amine molecules which interact with the framework through N,H···O hydrogen bonding. The compounds I,III bear some structural relationship to the layered zinc phosphite phases. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Fluorescence spectra of Pr3+ ions in phosphate materials calculated by the DVME methodINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 12 2009Y. Kowada Abstract Recently, fluorescence spectra of rare-earth ions in oxide materials are very attractive for the applications of the optical amplification in optical fiber communications, white LED, etc. However, it has been difficult to calculate the fluorescence spectra of rare-earth ions by the first principle method. In this study, we used the relativistic discrete-variational multielectron (DVME) method, which is a configuration-interaction (CI) calculation program using the molecular orbitals obtained by the relativistic DV-X, method. We applied this method for the calculation of the fluorescence spectrum of the Pr3+ ions in phosphate materials. The transition probability of the fluorescence was calculated in the same manner of the absorption. The obtained theoretical fluorescence spectrum was in good agreement with the experimental one, though the intensity of each peak was deeply dependent on the configuration of the surrounding structural units. The results suggested that the DVME method was useful for the calculation of not only absorption but also fluorescence spectra of rare-earth ions in oxide materials. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Conversion of Tetranary Borate Glasses to Phosphate Compounds in Aqueous Phosphate SolutionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2008Wenhai Huang In our earlier work, it was found that particles of a ternary alkali-borate glass, containing either CaO or BaO, converted completely to a crystalline phosphate of calcium or barium when reacted in an aqueous phosphate solution at 37°C. The present work is an extension of our earlier work to investigate the conversion of tetranary borate glass with the composition 10Li2O·10CaO·10(AeO or T2O3)·60B2O3 (weight percent), where Ae is the alkai-earth metal Mg or Ba, and T is the transition metal La, Sm, or Dy. In the experiments, particles of each glass (150,300 ,m) were reacted in 0.25M K2HPO4 solution with a starting pH of ,9.0 at 37°C. Weight loss and pH measurements indicated that the reaction was complete after 30,50 h, yielding an amorphous product. X-ray fluorescence showed that the as-formed product consisted of a calcium phosphate phase that contained the alkali-earth metal or transition metal present in the starting glass. Heating the as-formed material for 8 h at 600°,700°C produced a mixture of two crystalline phosphates: calcium phosphate and an alkali-earth or transition metal phosphate. The kinetics and mechanism of converting tetranary borate glass to phosphate materials are discussed and compared with data from earlier work for the conversion of ternary borate glass. [source] | ||||||||||